java 我如何隐藏空的 Velocity 变量名称？

How I hide empty Velocity variable names?

提问by Fernando Barrocal

I am using Struts + Velocity in a Java application, but after I submit a form, the confirmation page (Velocity template) shows the variable names instead an empty label, like the Age in following example:

我在 Java 应用程序中使用 Struts + Velocity，但在我提交表单后，确认页面（Velocity 模板）显示变量名称而不是空标签，如下例中的 Age：

Name: Fernando

Age: {person.age}

Sex: Male

姓名：费尔南多

年龄：{person.age}

性别：男

I would like to know how to hide it!

我想知道怎么隐藏！

回答by Jason Sparks

You can mark variables as "silent" like this:

您可以像这样将变量标记为“ silent”：

$!variable

If $variable is null, nothing will be rendered. If it is not null, its value will render as it normally would.

如果 $variable 为 null，则不会呈现任何内容。如果它不为空，它的值将像往常一样呈现。

回答by Nathan Bubna

You will also need to be sure and use the proper syntax. Your example is missing the dollar before the variable. It should be $!{person.age}, not just {person.age}.

您还需要确保并使用正确的语法。您的示例在变量之前缺少美元。它应该是 $!{person.age}，而不仅仅是 {person.age}。